The present invention relates to semiconductor devices and, more specifically, to an integrated device with P-I-N diodes and vertical field effect transistors.
In semiconductor device manufacturing, vertical transistors or vertical field effect transistors (VFETs) provide advantages over other types of transistors. Such advantages include, but are not limited to, the decoupling of gate length from contact gate pitch. As a result, recent efforts have been undertaken to explore the feasibility of using VFET devices to provide continued complementary metal-oxide-semiconductor (CMOS) scaling beyond 7 nm nodes.
Junction diodes such as P-I-N diodes, for example, are commonly used in a wide variety of products such as Radio Frequency (RF) switching devices, telecommunication devices, Electrostatic Discharge (ESD) protect devices, image sensors, and the like. P-I-N diodes are diodes with wide, un-doped intrinsic semiconductor regions between p-type and n-type semiconductor regions. P-I-N diodes this have three layers. These include a P-doped semiconductor layer (P), an intrinsic layer (I) and an N-doped semiconductor layer (N). P-I-N diodes can also be used as photodetectors or optical receivers. For example, when exposed to light illumination, a current is generated in the P-I-N photodiodes and the magnitude of the current depends on the intensity of the light. When no light illumination is present, the photodiode can be reversed biased and almost no current is generated.
P-I-N junctions can also be used in various types of semiconductor devices that often require transistor elements for other applications. Where such semiconductor devices are scaled down to 7 nm node sizes or less it becomes necessary to incorporate VFETs and P-I-N diodes on the same semiconductor device substrate.